Stabilized ammonium humate coating for fertilizer granules

ABSTRACT

A stabilized ammonium humate mixture including an amount of humic acid between about 7.0% to about 10% of the mixture and an amount of ammonia between about 1.0% to about 14% of the mixture, where the remainder of the mixture is water. The stabilized ammonium humate mixture has a pH between about 9 to about 11.

BACKGROUND

Modern agriculture has seen an increase in the use of various granularchemical fertilizers, such as urea, ammonium sulfate, mono-diammoniumphosphate, potassium nitrate, and so on. These may be applied to thesoil at a rate of tens of pounds per acre up to hundreds of pounds peracre, and these granular fertilizers may also be the main source ofnutrients for plants. It is known that use of mineral fertilizers andother chemicals may have resulted in the loss of soil organic andmineral matter, the suppression of native microbial populations, thedisturbance of natural pH levels, the reduction of soil absorbingcapacity, and generally result in soil degradation. This also negativelyimpacts soil fertility. Furthermore, plants only typically consume aboutone-half of the fertilizer applied to agricultural fields.

The remainder of the fertilizer applied to agricultural fields may seepinto the ground water or run-off, and may be a primary contributor towater pollution, called eutrophication. Generally, the more degradedsoil is, the more extensive the problem. Nitrogen fertilizer, andespecially urea, may be the most destructive for native soilcomposition, properties, and functions. Nitrogen loss may be between 25%to 75% as a result of ammonia volatilization, nitrification, anddenitrification, which is why nitrogen management in soil, including itsstabilization and buffering is important.

One traditional method for reducing the loss of nitrogen, phosphorus,and potassium is coating a mineral fertilizer with a polymer, fat,grease, or sulfur. These form what are referred to as “slow release” or“control release” fertilizers, as coating with natural andchemical/synthetic agents slow down the fertilizers solubilization,ammonia volatilization, nitrification, and/or denitrification, as wellas the reduction in phosphate immobilization by soil ions thus keepingthe nutrients available longer for plants.

Another conventional method for dealing with the above-mentionedproblems is a urease inhibitor, which may slow ammonia volatilization.However, urease inhibitors may also have a negative impact on the plantand cause necrosis due to urea accumulation in plant tissue.Furthermore, urease inhibition may also result in the suppression of awide group of soil bacteria that use urease as a tool for nitrogenuptake, which may lead to an imbalance of native soil microbialpopulations and could even potentially result in an influx of pathogenicmicrobial species. There are also nitrification inhibitors (e.g. N-SERV24 Nitrogen Stabilizer™), which may depending on soil conditions, slowthe nitrification process. While such products may inhibit nitrifyingbacteria (i.e. a group of bacteria which convert ammonium intonitrites/nitrates), they may also be hazardous for humans and toxic forthe environment.

The above referenced methods for reducing nitrogen loss may be viscousliquids and once applied to a fertilizer granule results in a stickysurface making the granules prone to build up and granule agglomerationinto large chunks/lumps. This agglomeration may clog transporters,hoppers, spreading system, etc. Viscosity may be temperature dependent;for example, at lower temperature the viscosity may increase resultingin increased stickiness and agglomeration. Furthermore, the freezingtemperatures of these conventional methods of reducing nitrogen loss arerelatively high (e.g. slightly below or close to 32 F), which makestheir application problematic in late fall or early spring.

Other methods of addressing the issue of nitrogen loss include mixingurea with acidic materials alone or also with humic and fulvic acids.The acidic material binds ammonia into ammonium salts, thus reducingammonia volatilization; however, this method does result in mobileammonium salts as well as nitrite/nitrate salts that may be leached. Insome instances, mixing urea with acidic materials and humic/fulvic acidsmay reduce ammonia loss as compared to urea alone and increased ammoniumand nitrate content in soil as compared to urea alone. However, thissuch mixing adds extra cost to urea nitrogen fertilizer, andfurthermore, adding humic/fulvic acids to the mixture may result ingranules agglomeration to large chunks/lumps that may clog transporters,spreading systems, etc.

SUMMARY

The present invention relates to primal plant's nutritional nitrogen, aswell as phosphorus and potassium management by their stabilization andbuffering in soil by coating N—P—K fertilizer granules with liquidstabilized ammonium humate (“SAH”) that is extracted from brown coal(lignite, leonardite) with application of diluted aqueous ammonia.

In an aspect, a stabilized ammonium humate mixture includes: an amountof humic acid ranging between about 8.0% to about 10% of the mixture;and an amount of ammonia ranging between about 1% to about 14% of themixture, and where the remainder of the mixture is water; and where thestabilized ammonium humate mixture has a pH between about 9.5 to about11.

In some embodiments, the amount of ammonia ranges between about 7% andabout 9.5%. In other embodiments, the amount of ammonia ranges betweenabout 9% and about 10%. In other embodiments, the amount of humic acidranges between about 8.5% and about 9.5%. In some embodiments, the pH isabout 11.

In some embodiments, the mixture is configured to coat a mineralfertilizer granule. In some such embodiments, the mineral fertilizergranule is a urea granule.

In another aspect, a method of manufacturing stabilized ammonium humate,includes: obtaining a humic acid containing material with a particlesize of about 3 millimeters or less; heating water to about 50° C. toabout 55° C.; mixing the heated water with an about 25% to about 30%aqueous ammonia solution at a ratio ranging between about 2:1 to about1:1 to form a diluted aqueous ammonia; adding the humic acid containingmaterial to the diluted aqueous ammonia at a ratio of 1:5; mixing thehumic acid containing material and the diluted aqueous ammonia forming aslurry; separating the slurry into a supernatant and a precipitate,where the supernatant is the stabilized ammonium humate and sediment.

In some embodiments, the particle size is about 1 millimeter to about 3millimeters. In some embodiments, the ratio of heated water to the about25% to about 30% aqueous ammonia is 2:1. In other embodiments, themixing of the humic acid containing material and the diluted aqueousammonia is for about 20 minutes.

In some embodiments, the ratio of heated water to the about 25% to 30%aqueous ammonia is about 28:1.

In some embodiments, the supernatant has a yield of about 76% to about80%. In some embodiments, the supernatant has a dissolved solid contentof about 11.0% to about 12.5%. In some embodiments, the supernatantincludes about 9.0% to about 11.5% humic acid.

In some embodiments, separating the slurry into the supernatant and theprecipitate is by gravity.

In still yet another aspect, a method of nutrient management of soilincludes: obtaining stabilized ammonium humate mixture/solution, wherethe mixture/solution includes: humic acid ranging between about 8.0% toabout 10% of the mixture and an amount of ammonia ranging between about1% to about 14% of the mixture, where a remainder of the mixture iswater, and where the stabilized ammonium humate mixture has a pH betweenabout 9.5 to about 11; mixing the stabilized ammonium humate with afertilizer granule at a dosage of about 0.5 to about 1.0 gallons of thestabilized ammonium humate per ton of fertilizer.

In some embodiments, the fertilizer is a urea granule.

As used herein the term “nitrogen stabilization” means the prolongedexistence of nitrogen in soil in forms that are available for plants andsoil microorganisms without, or in reduced rate, of nitrogen loss due toleaching, volatilization, nitrification, and/or denitrification.

As used herein the term “buffering” means the prolonged existence ofammoniacal and/or nitrate nitrogen in soil due to the ability of thesoil to keep these substances without rapid conversion into othernitrogen forms that are not available to plants, for example gaseousammonia, gaseous nitrous oxides, and gaseous molecular nitrogen.

When used herein, in both the specification and claims, the term “about”used an adverb rather than as a preposition means “approximately” andcomprises the stated value and every value within 10% of that value; inother words, “about 100%” includes 90% and 110% and every value inbetween.

DETAILED DESCRIPTION

As described in detail herein, stabilized ammonium humate may be used asmineral fertilizer coating. Stabilized ammonium humate treatedfertilizer granules may dry rapidly, which minimizes the agglomerationof the granules. Furthermore, the stabilized ammonium humate coating mayreduce nitrogen loss, facilitate storage of phosphate and potassium informs available for plant use, support native soil microorganisms, andstimulate seed germination, plant growth, and development.

Conventional methods of manufacturing ammonium humate have a number oflimitations. For example, the slurry formed of brown coal and aqueousammonia may contain excess amounts of dissolved ammonia, hydrated andhydrolyzed coal particles (in which there is some bitumen, mineralcarbon, aluminum, iron, manganese, etc. oxides/hydroxides, silicates,etc.), and water. The separation of the particulate matter and liquidsolution is both time and labor intensive because the brown coalparticles in the slurry may swell resulting in sticky/tacky sediment. Asanother example, the resulting solution has a low percentage of ammoniumhumate (ammonium salt of humic acid) and a high pH (approximately 12),which may result in the product being classified as “highly corrosive”along with the corresponding restrictions on manufacture, storage,transportation, and handling. The strong ammonium smell may be anadditional limiting factor, as it may cause a reaction among workersand/or create an unpleasant working environment. Additionally, theslurry or separated liquid particulate matter from these methods may notbe used as a coating for a fertilizer granule, because it is likely toclogs pipes, spraying heads, etc. Another limiting factor may be thefreezing temperature of liquid ammonium humate, which may make theammonium humate thick, icy, difficult to pump, or even frozen at lowambient temperatures. For example, in the northern United States (andother countries) coating of granular fertilizers and application of thesame to soil may begin in late winter to early spring when temperaturemay be below 32° F. (0° C.). Low temperatures in these regions may be aslow as minus 12° F. (−24° C.) when some farmers begin “early spring”fertilizer addition to soil. In most instances, the ambient temperaturesin these regions may be around 26° F. (−3° C.) during the fertilizerpreparation and application to soil. Furthermore, the transportation ofammonium humate during colder seasons, along with its storage innon-conditioned warehouses, may result in freezing into a thick and icymaterial that makes application as liquid additive/coating tofertilizers difficult. Heating of the frozen material allows it toreturn to its original state (liquid, easy flowing, pumpable material),but requires time, labor, and energy thus making the material moreexpensive and inconvenient to use.

An improved method of manufacturing a stabilized ammonium humate liquidwith higher humic acid content, higher supernatant yield (i.e. lesssediment), improved fluidity, lower pH, lower freezing temperature, andreduced corrosiveness and ammonia smell is desired.

Analyses were conducted in order to evaluate the effect of variousparameters and conditions. In a first example, commercial aqueousammonia with a 28% wt. concentration may be blended with lignite at aratio ranging from 1:20 to 1:5 lignite to aqueous ammonia by mass untila stable slurry is formed in order to extract humic acid. In someinstances, a ratio below 1:5, for example 1:4, 1:3, etc. may make theslurry too heavy and concentrated for mechanical treatment (e.g. mixing,pumping, etc.). In some instances, a ratio above 1:20, for example 1:22,etc. may make the slurry too diluted for humic acid extraction. Thisprocess may be carried out at ambient temperature. After sedimentprecipitation and supernatant removal, the supernatant/solution wasanalyzed on dissolved solids content (primarily humic and fulvic acids).The humic acid content (“California Method”), pH, and percent yield ofthe solution were determined. The results are presented in Table 1below.

TABLE 1 Lignite:Aqueous Dissolved Solids Humic Acid Solution AmmoniaRatio Content Content Yield pH 1:20 2.52% 1.74% 96.1% 12.06 1:10  4.6%3.61% 79.2% 11.8   1:6.5 6.92% 5.08% 67.5% 11.7 1:5 8.66%  6.7%   59%11.6

As illustrated by the results of Table 1, the higher the lignite contentthe greater the dissolved solids (and humic acid) content in thesupernatant and the less supernatant yield. The maximum dissolved solids(and humic acid) content was achieved with a lignite to aqueous ammoniaratio of 1:5 but was also the lowest solution yield (59%); therefore,roughly 41% of the slurry swelled, generating a sticky, adhesivesediment that is waste product. The lowest lignite to aqueous ammoniaratio, 1:20, resulted in the lowest dissolved solids (and humic acid)content. The freezing temperature of these products may be below −20° F.(−28° C.). Each of the presented in Table 1 have a strong ammonia smell.

The efficacy of the process may not be able to be improved by increasingthe temperature of original/commercial aqueous ammonia, becauseintensive ammonia release and water evaporation may result. Furthermore,an increase in the mixing time may result in an increase in sedimentswelling, higher volume of sediment or a lower supernatant yield.

The dominating functional groups in humic acid are carboxylic (—COOH)and phenolic (>OH) groups, and most of the properties and functions ofhumic acid are a result of activity of these functional groups. Theschematic formula for humic acid (and fluvic acid) is presented asfollowing:

Where “Hum” is the volumetric part of humic acid molecules with phenolichydroxide (OH) functional group in them and “COOH” is a carboxylicfunctional group.

Ammoniacal nitrogen (ammonium cation) has a high affinity for phenolichydroxide, which may result in the replacement of protons (hydrogencations) with ammonium cations. Where the ammonium concentration is low,all of the ammonium may be bonded by phenolic groups according to thedescribed ion exchange mechanism. Where the ammonium concentration ishigher and all phenolic groups are already saturated (e.g. bonded) withammonium, then ammonium may also replace the hydrogen cation in thecarboxylic groups, resulting in a molecule “saturated” with ammonium, ora ammonium saturated molecules of humic acid. The schematic formula forsuch a molecule is presented below:

Generally, ammonium saturated humic acid may be the result of theextraction of humic acid with original/commercial aqueous ammoniacontaining an ammonia content ranging from about 25% to about 30%(commercially available reagents with maximum ammonia content).

Original/commercial aqueous ammonia that is diluted with water mayinteracts with the humic acid in brown coal differently than undilutedaqueous ammonia (e.g. aqueous ammonia with an ammonia content rangingfrom about 25% to about 30%). Use of a diluted aqueous ammonia mayresult in an increase in the amount of humic acid extracted, as well ahigher humic acid content in the final product and a lower pH.Furthermore, the efficacy of extraction may increase where the waterused to dilute the aqueous ammonia is heated.

Analyses were conducted in order to evaluate the effect of variousconcentrations of diluted aqueous ammonia and reaction temperature.Commercially available aqueous ammonia with a concentration of 28% wasdiluted to the desired concentration through the addition of water. Thehumic acid content (“California Method”), pH, and percent yield andapproximate freezing temperature of the solutions were determined. Theresults are presented in Table 2 below.

TABLE 2 Lignite: Appx. Ammonia Diluted Water Freeze content AqueousTemp. Dissolved Humic Temp. Ex after Ammonia (degrees Solids AcidSolution (degrees # dilution Ratio C.) Content Content Yield pH F.) 1  14% 1:5 Ambient  10.4%  8.1% 74% 11.3 −12 2   14% 1:5 50-55  11.4% 8.9% 75% 11.3 −12 3 9.33% 1:5 Ambient 11.24% 8.94% 76% 10.9 12 4 9.33%1:5 50-55 12.22% 9.57% 76% 10.8 12 5    7% 1:5 Ambient  11.8%  9.2% 76%10.9 14 6    7%  1:6.5 Ambient  7.84%  6.1% 72% 11.1 14 7  5.6% 1:550-55 10.74%  8.4% 76% 10.7 16 8    4% 1:5 50-55  10.6%  8.3% 76% 10.617 9  2.8% 1:5 50-55  10.5%  8.2% 76% 10.2 18 10    1% 1:5 50-55   8.7% 6.8% 76% 8.8 23 11  0.5% 1:5 50-55   5.4%  4.2% 76    7.4 28

As is illustrated by Examples 1 and 2, in Table 2, which are identicalother than the water temperature, heating the water used to dilute theaqueous ammonia to about 50 degrees Celsius to about 55 degrees Celsiusprior to mixing with the aqueous ammonia results in an increase indissolved solids content and humic acids content. Not illustrated by thedata of Table 2, in Examples 2 and 4 the temperature of the waterdropped to about 42 degrees Celsius to about 45 degrees Celsius afteradded to the commercially available aqueous ammonia with a concentrationof 28%.

As generally illustrated by the results of Table 2, use of a dilutedaqueous ammonia may result in a higher quality supernatant with a highercontent of dissolved solids and humic acid, a higher yield, a lower pH,and acceptable freezing temperature. Furthermore, the lower the ammoniacontent after dilution, the less ammonia smell is present. The resultspresented above indicate that a water to aqueous ammonia ratio from 1:1(14% ammonia concentration) to 9:1 (2.8% ammonia concentration) mayyield the best results; while a lignite to aqueous ammonia solution of1:5 may yield the best results. As illustrated in Table 2, these ammoniaconcentration result in higher dissolved solids/humic acid content, a pHat about 11 and below, and a low freezing temperature—around 18 F andbelow; however, the ammonia smell may still be significant. Furthermore,the lower the ammonium content the less ammonia volatilization, thusreducing the smell and irritation to eyes, skin, and respiratory systemduring the product manufacture and application. No to minimal ammoniasmell may be present where the water to aqueous ammonia ratio is about28:1 (total ammonia content is about 1%) or less (for example, totalammonia content 0.5%). However, these ammonia contents, for example witha total ammonia content of 0.5% may result in low dissolved solidscontent (5.4%) and humic acid content (4.2%). This is why a minimumammonia content of about 1% may be preferable.

The higher efficacy resulting from the use of diluted aqueous ammonia inthe extraction of humic acids may be based on the chemisorption ofammonia (NH₃) with water molecules (H₂O), which results in aqueousammonia [NH₃—H]⁺—OH⁻, which is also known as ammonium hydroxide NH₄⁺(OH)⁻. Dilution of the aqueous ammonia results in less ammonia byvolume, more ammonia ionization to ammonium, and an increased rate ofreplacement of exchangeable protons and metals cations of humic acid byammonium. Furthermore, the diluted solution may also have an increasedbuffering ability, which may facilitate humic acid remaining in the formof dissolved stabilized ammonium humate.

Therefore, in accordance with the examples presented with reference toTable 2, the materials for manufacturing a stabilized ammonium humatemay include water heated for about 50-to about 55 degrees Celsius,commercially available aqueous ammonia with ammonia concentration 25% toabout 30%, and brown coal. In some instances, the brown coal may beground to maximum particles size of about 1 mm to about 3 mm prior tothe reaction.

In some instances, water is added to a reactor or mixer once heated tothe desired temperature (about 50 to about 55 degrees Celsius) the watermay be pumped into the reactor or mixer; in other instances, the watermay be heated in the reactor or mixer to the desired temperature. Thecommercially available aqueous ammonia may then be pumped into thereactor or added to the mixer. In some instances, the addition of theaqueous ammonia may be done slowly while mixing with the heated water,so as to avoid release of excessive ammonia to the atmosphere. In someinstances, the temperature of the water may be closely monitored. Theboiling temperature of aqueous ammonia is 60 degrees Celsius, and addingaqueous ammonia to water that is about 60 degrees Celsius or highercould result in excessive ammonia being released. Conversely, in someinstances, where the water temperature is lower than about 50 to about55 degrees Celsius, for example when the water temperature is about 40degrees Celsius to about 45 degrees Celsius, the mixing with thecommercially available aqueous ammonia may result in the mixture have atemperature around 30 degrees Celsius, which may lead to a decreasedyield of humic acid. However, where the water temperature is about 50 toabout 55 degrees Celsius, the mixing with the commercially availableaqueous ammonia may result in the mixture have a temperature around 42degrees Celsius to about 45 degrees Celsius and effective humic acidextraction.

In an example, stabilized ammonium humate as described herein may bemanufactured in a 4,000 gallon (15,140 liter) mixer with a 3,600 gallon(13,626 liter) working capacity. Approximately 2,006 gallons (7,593liters) of water may be heated up to temperature between about 50degrees Celsius and about 55 degrees Celsius and pumped into thereactor. In other instances, the water may be heated to about 50 degreesCelsius and about 55 degrees Celsius within the reactor itself. Apropeller type mixer may be used, and approximately 1137 gallons (4304liters or 3856 kg) of commercially available aqueous ammonia (28%concentration) with an ambient temperature (about 22 degrees Celsius)may be added to the reactor. The mixing is not limited to a propellertype mixer, and may be done with other types of mixers, blenders, etc.known in the art. The mixing of the heated water and aqueous ammonia mayresult in the mixture having a temperature of about 45 degrees Celsius.Following the mixing of the heated water and the aqueous ammonia, about5438 lbs. (2466 kg) of lignite was added to the reactor, which mayresult in lignite interaction with the aqueous ammonia solution withoutprecipitation. In the example presented herein, the water, aqueousammonia, and lignite may result in a total volume equal to approximately3,600 gallons, or working capacity of the reactor. In the examplepresented herein, the ratio of heated water to aqueous ammonia is about2:1, and the ration of lignite to diluted aqueous ammonia is about 1:5.The diluted aqueous ammonia and lignite may be mixed for about 20minutes. However, this time period is not to be construed as limiting,as in some instances the mixing time may be shortened or lengthened.

Following the mixing, the reactor may be turned off and the mixture maybe transported (e.g. through pumping) to a storage tank where sedimentmay precipitate. Once the sediment has precipitated for about 12 toabout 24 hours, supernatant may be removed (e.g. through pumping) andused. The supernatant may have a yield of about 76%. The pH of thesupernatant may be about 10.8, with a solid content of about 11.9%,9.15% of which being humic acid. The supernatant may be meet variouscommercial regulations for labeling as nontoxic,inflammable/incombustible, noncorrosive, but may be classified as a mildskin and eye irritant with an ammonia smell. Its freezing temperaturemay be approximately 12 degrees F. This may allow for use acost-effective agricultural product without the restrictions of manyother ammonia-based products.

As a result of the described process, stabilized ammonium humate isproduced and the ammonium volatilization into ammonia is significantlyreduced as compared to known processes. The sediment resulting from theprocess is not used in the generation of saturated ammonium humate andmay sold or given away for other uses. The resulting stabilized ammoniumhumate (“SAH”) was tested as a coating agent on urea, mono-diammoniumphosphate, ammonium sulfate, potash (potassium chloride) granules; thestabilized ammonium humate was also tested as a component of mix ofthese granulated fertilizers.

When the urea 46-0-0 granules were coated with the SAH to a dose of 0.5gallons/ton the resulting coating granules are dry due to the rapidabsorption and partial evaporation of the water. When the urea 46-0-0granules were coated with the SAH to a dose of 1.0 gallons/ton theresulting coating granules are slightly wet, and the conversion to a drystate takes approximately 10-15 minutes. When the urea 46-0-0 granuleswere coated with the SAH to a dose of 1.5 gallons/ton the resultingcoating granules are wet, resulting in some aggregation of the granules;furthermore, drying takes more than 30 minutes. This indicates that adose of 0.5-1.0 gallon/ton may be desirable. The testing described belowutilizes urea granules coated at a dose of 0.5 gallons/ton of SAH; thecoated urea was initially slightly wet but dried within a few minutes.

There may be several mechanisms of nitrogen loss in soil. Somenon-limiting examples of nitrogen loss include: urea may rapidlydissolve and seep through the soil profile; urea may decompose resultingin ammonia volatilization to the atmosphere; nitrification may result innitrates leaching from the soil; and, denitrification may result in therelease of nitrous oxides and molecular nitrogen into the atmosphere.

The SAH coating on urea granules may alter the mechanisms of nitrogenloss described above. The interaction between urea (NH₂)₂CO and the SAHmolecules disposed on the surface of the urea granules may be describedas the following:

This interaction may result in complex “urea-humic” molecules calledadducts with hydrogen type bonds between them. In adduct molecules bothconstituents keep the features each had before the interaction. Somerelease of ammonia (HN_(3 excessive)) may be detectable here.

SAH coated urea dissolves in soil (due to soil moisture) slower thatuncoated urea resulting in “slow release” fertilizer. The naturalprocess of urea decomposition to ammonium hydroxide NH₄OH (followed byammonia volatilization) and carbonic acid H₂CO₃ (followed by carbondioxide release) is primarily caused by enzyme (urease) activity in soiland can be described as the following schematic formula:

The formation of ammonium hydroxide results from the interaction of ureawith the naturally dried SAH coating results in SAH solubilization anddiffusion into soil. SAH molecules, as well as the ammonium hydroxideassociated with them, may be more attracted to (or adhesive to) organicand/or mineral matter in the soil than original ammonia/ammonium.Therefore, the soil may absorb more ammonium in the SAH form thanammonia/ammonium.

Once absorbed by soil particles, ammonium nitrification may result inacidic anions of nitrite and nitrate, which are nitrous (HNO₂) andnitric (HNO₃) acids. This results in soil acidification.

The interaction of, for example, nitric acid and SAH may be illustratedby the following schematic formula:

The Ammonium in the carboxyl group may be completely replaced by acidichydrogen cations (via ion exchange mechanism). While, the ammonium inthe phenolic group may be less available for replacement by protons dueto stronger bonds between ammonium and oxygen in phenolic groups; onlystrong acidity may result in ammonium replacement in these groups.Therefore, ammonium replacement by protons in carboxylic group mayresult in humic coagulation into insoluble fine/colloidal watersaturated associates (e.g. flakes)—the fundamental humic acid property:to dissolve in interaction with alkali and to coagulate in interactionwith acid. Nitrate-ions may be occluded into coagulated volumetricstructures; in other words, nitrates may be immobilized, eliminating orlimiting their ability to migrate through the soil profile. As a result,the nitrate may not be leached away because the coagulated humicmolecules may be tightly bound with soil particles due to“hydrophilic-hydrophilic” and “hydrophobic-hydrophobic” interactions.Protons (H⁺) remain mobile because of their low mass and size, but theydo continue to be in and around coagulated humic associates (flakes) dueto their cation exchange capacity CEC (positively charged protons areattracted by negatively charged nitrate and humic/hulvic acidsnegatively charged sites) thus keeping coagulated humic electricallyneutral). Exchangeable ammonium may interact with non-occluded nitratesresulting in ammonium nitrate (NH₄NO₃), but this is not the dominatingprocess and only minor ammonium nitrate formation is possible.

Nitrates may be occluded in coagulated humic structures, resulting inmost nitrates being unavailable for leaching and migration from top soilin deep layers as the occluded nitrates stay on the top soil andavailable for adsorption by plant root system.

The SAH produced according to the embodiments described herein was alsotested in field tests. The SAH was added to urea granules at a dosingratio of one-gallon SAH to one ton of urea granules and mixed for about2 to about 3 minutes, resulting in urea granules with a homogeneouscoating of SAH. The slightly wet coated urea granules dry in around 10minutes without aggregation of the urea granules, tackiness, etc. Coatedurea granules may be able to easily flow in all processes of loading,unloading, spreading, etc.

Field spots were prepared for three types of tests sites: (1) control;(2) SAH coated urea; and (3) urea coated with other commercialpreparations (nitrogen stabilizers) in recommended doses. Each wereapplied at appropriate doses and corn seeds were planted in accordancewith local agrochemical practice.

The nitrogen content in the soil in form of nitrates (in ppm andlbs./acres) was measured before and after test (3 months) in all fieldspots. Available phosphorus and potassium were also measured before andafter test. The results are presented in Table 3 below.

TABLE 3 Nitrate Nitrate Phosphorus Potassium Treatment (ppm) (lbs./acre)(ppm) (ppm) Control 5.7 14 116 518 SAH 23.9 57 170 710 Nutrisphere-N ®9.5 23 116 534 Azoteren Aeris 7.9 19 94 567 Azoteren Stratum 8.1 20 152637 Instinct ® HL 16.4 39 168 493 Agrotain ® Advanced 1.0 12.9 31 132573

SAH demonstrates increased nitrogen stabilization as well as availablephosphorus and potassium content in soil in comparison with control andcommercially available fertilizer coatings. For example, the SAHtreatment demonstrates a nitrate measurement of 23.9 ppm 3 monthsfollowing treatment versus 5.7 ppm in the control and 9.5 ppm in thecase of treatment with Nutrisphere-N®. Furthermore, there are 57lbs./acre of nitrate where the SAH treatment was applied, 14 lbs./acreat the control site, and 23 lbs./acre where Nutrisphere-N® was applied;in other words, treatment with SAH allowed 3.07 times greater nitrogencontent in soil as compared with the control and 1.48 times greaternitrogen content in comparison with Nutrisphere-N®.

At the same time, treatment with SAH also results in higher availablephosphorus—170 ppm with SAH treatment versus 116 ppm in the control and116 ppm with Nutrisphere-N®. This is approximately a 46.6% increase inthe available phosphorus content in comparison with the control and theNutrisphere-N® treatment. Furthermore, treatment with SAH results in anincrease in available potassium; for example treatment with SAH yields710 ppm of available potassium versus 518 ppm in the control and 534 ppmwhen treated with Nutrisphere-N®. This is approximately a 37% increasein available potassium in comparison with the control and approximatelya 32.9% increase in comparison with Nutrisphere-N®. As demonstratedherein, SAH improves soil composition, properties and functions. Becauseof this, the application of SAH also reduces the amount of fertilizernecessary by approximately 20 to 50%.

Although described herein with respect to coating urea granules, the useof the described stabilized ammonium humate (SAH) is not so limited. Itis to be understood that SAH may be used to coat other types offertilizer granules in order to manage nitrogen, phosphorus, and/orpotassium release into the soil.

What is claimed is:
 1. A stabilized ammonium humate mixture/solution,comprising: an amount of humic acid ranging between about 7% to about10% of the mixture; and an amount of aqueous ammonia ranging betweenabout 1% to about 14% of the mixture; wherein a remainder of the mixtureis water; wherein the water and aqueous ammonia form an ionized ammoniumhydroxide, and the ionized ammonium hydroxide and the amount of humicacid thereby form stabilized ammonium humate mixture; and wherein thestabilized ammonium humate mixture has a pH between about 9 to about 11.2. The stabilized ammonium humate mixture of claim 1, wherein the amountof ammonia ranges between about 7% and about 9.5%.
 3. The stabilizedammonium humate mixture of claim 1, wherein the amount of ammonia rangesbetween about 9% and about 10%.
 4. The stabilized ammonium humatemixture of claim 1, wherein the amount of humic acid ranges betweenabout 7% and about 9%.
 5. The stabilized ammonium humate mixture ofclaim 1, wherein the mixture is configured to coat a mineral fertilizergranule.
 6. The stabilized ammonium humate mixture of claim 5, whereinthe mineral fertilizer granule is a urea granule.
 7. A method ofmanufacturing stabilized ammonium humate, comprising: obtaining a humicacid containing material with a particle size of about 3 millimeters orless; heating water to about 50° C. to about 55° C.; mixing the heatedwater and an about 25% to about 30% aqueous ammonia solution at a ratioranging between about 1:1 to about 28:1 to form an ionized ammoniumhydroxide; adding the humic acid containing material to the ionizedammonium hydroxide at a ratio of 1:5; mixing the humic acid containingmaterial and the ionized ammonium hydroxide forming a slurry; separatingthe slurry into a supernatant and a precipitate, wherein the supernatantis the stabilized ammonium humate and sediment.
 8. The method of claim7, wherein the particle size is about 1 millimeter to about 3millimeters.
 9. The method of claim 7, wherein the ratio of heated waterto the about 25% to aqueous ammonia is 2:1.
 10. The method of claim 7,wherein the mixing of the humic acid containing material and the ionizedammonium hydroxide is for about 20 minutes.
 11. The method of claim 7,wherein the supernatant has a yield of about 76% to about 80%.
 12. Themethod of claim 7, wherein the supernatant has a dissolved solid contentof about 9% to about 12%.
 13. The method of claim 7, wherein thesupernatant includes about 7.0% to about 10.0% humic acid.
 14. Themethod of claim 7, wherein separating the slurry into the supernatantand the precipitate is by gravity.
 15. A method of nutrient managementof soil, comprising: obtaining stabilized ammonium humate mixture,wherein the mixture includes: humic acid ranging between about 7.0% toabout 10% of the mixture, and an amount of ammonia ranging between about1% to about 14% of the mixture, wherein a remainder of the mixture iswater, and wherein the stabilized ammonium humate mixture has a pHbetween about 9 to about 11; mixing the stabilized ammonium humate witha fertilizer granule at a dosage of about 0.5 to about 1.0 gallons ofthe stabilized ammonium humate per ton of fertilizer.
 16. The method ofclaim 15, wherein the fertilizer granule is a urea granule.